1. Field of the Invention (Technical Field)
The present invention relates to user interface with a telephone, in particular to the navigation keys of a mobile telephone handset.
2. Background Art
Mobile handsets typically comprise a rigid housing enclosing a printed circuit board, the associated electronic and electro-acoustic components, and an antenna, through which radio frequency (RF) signals are transmitted and received. The telephone user interfaces with the circuitry and microprocessor of the mobile through a keypad located on the front outer surface of the housing. This keypad is located on the same face of the housing as the microphone and speaker through which the user speaks and listens during communication. Keys on the keypad are pressed by the user to temporarily close an internal electronic switch and send a signal to the microprocessor of the mobile where an appropriate routine processes the input and operates the mobile. Graphical elements, such as alphanumeric characters and icons, are located on or near the keys to guide the user in interfacing with the mobile. For example, keys are identified with the numbers 0–9, letters of the alphabet, and the pound and asterisk symbols. Backlighting is provided on most mobiles to enhance the visibility of the keys and associated user interface graphical elements. A display above the keypad on the housing provides spatially-navigated menu trees, graphical user interface (GUI) windows, messaging, and readouts of data input by the user.
As mobile designs advance, more features are offered to the user, such as the ability to program and store information. One such feature is the ability to program the memory to store telephone numbers that are frequently dialed. A series of menus shown on the display aid the user in inputting this and other types of data, and also aid the user in accessing data. These features require an increasing number of keys and more detailed information on the display for the user to efficiently interface with the mobile. There are a variety of function keys provided on mobile handsets that are used to access these features. Navigation keys are a type of function key frequently used to spatially navigate through mobile GUIs and menu trees. These keys provide the ability to move up, down, left, or right within a menu, or to move a cursor within text or a numeric display. Navigation keys are typically located on the side of the mobile handset housing away from the main keypad, or they may comprise individual keys on the main keypad. They are usually identified with arrows indicating the direction of movement that the key provides. The up and down navigation keys are often used to move within menu options. Once the user has navigated to the desired location within a menu, the option is selected with an enter key. Left and right navigation keys are used to move in the up, down, left, and right directions within menu options, to move the cursor on a display. The left navigation key is also often used to delete incorrect data entry.
As the number of keys on the keypad of a mobile increases, the density of the keys within a given surface area increases and the size of each key decreases. Key spacing is further compromised as mobiles are made more compact to reduce weight and improve portability. This causes user interaction with the keys to be more cumbersome. Four navigation keys add to the already crowded keypad area and compete for space on the housing. The present invention increases the number of functions that a given key on a mobile keypad performs thereby decreasing the number of keys required, decreasing the key density on the keypad, and allowing for increased key size.